Where is the error in my Python code (MQTT)?

I created a Python script so that certain commands can be executed later when messages are received. For the first script (Openhab_Mqtt.py), I opened three terminals while testing, and for the second (Openhab_Mqttv2.py), I used exactly the same procedure.

In the first terminal I started the Python script with:

 python Openhab_Mqttv2.py

Output:
Script 1: Connected to MQTT broker
Script 2: Connected to MQTT broker
Connected to MQTT broker

In the second terminal I displayed the message for messages with:

 mosquitto_sub -t "main/messager" -v -u xxx -P xxx

Output (after T3):
Script 1: main/messager test
Script 2: main/messager test

And in the 3rd terminal I sent a message with:

 mosquitto_pub -t "main/messager" -m "test" -u xxx-P xxx

Output:
Script 1: Payload: test and BLA…
Script 2:

I just can't find the error why it works for Openhab_Mqtt.py and not for Openhab_Mqttv2.py.

Openhab_Mqtt.py DATA:

 import paho.mqtt.client as mqtt import os import time import bme280_temp import smbus2 import bme280 import threading def on_subscribe(client, userdata, mid, granted_qos): print("Subscribed to topic : " + str(mid) +" with QoS" + str(granted_qos)) def on_connect(client, userdata, flags, rc): print("Connected to MQTT broker") def on_message(client, userdata, msg): print(msg.topic+" "+str(msg.qos)+" "+str(msg.payload)) print("Payload: " + msg.payload.decode()) if msg.payload.decode() == "send_signal": print("Calling script to send signal...") IR_Signal() if msg.payload.decode() == "temp_bme280_start": print("Calling script to for temperature start...") userdata["counter"] += 1 print(str(userdata["counter"])) client.publish("frame/monitor", "START", qos=0, retain=True) Temp_sensor() if msg.payload.decode() == "temp_bme280_stop": print("Calling script to for temperature stop...") userdata["counter"] -= 1 print(str(userdata["counter"])) client.publish("frame/monitor", "STOP", qos=0, retain=True) if msg.payload.decode() == "test": print("BLA...") print(str(["counter"])) os.system("vcgencmd measure_temp") else: pass #Bme280_basic Temperature address = 0x76 bus = smbus2.SMBus(1) calibration_params = bme280.load_calibration_params(bus, address) def Temp_sensor(): data = bme280.sample(bus, address, calibration_params) temperature_celsius = data.temperature print("Temperature: {:.2f} °C".format(temperature_celsius)) time.sleep(2) def IR_Signal(): os.system("irsend SEND_ONCE pioneer_vsx-301 KEY_POWER") print ("Signal Send!") client = mqtt.Client() client.on_message = on_message client.on_connect = on_connect client.user_data_set({"counter": 0}) client.username_pw_set( "xx" , "xx" ) client.connect( "192.xxx", 1883, 60) client.subscribe( "main/messager" , qos=0) client.loop_forever()

Openhab_Mqttv2.py

 import paho.mqtt.client as mqtt import time import smbus2 import bme280 import threading # Getting information def on_subscribe(client, userdata, mid, granted_qos): print("Subscribed to topic : " + str(mid) +" with QoS" + str(granted_qos)) def on_connect(client, userdata, flags, rc): print("Connected to MQTT broker") # Damit loops nicht am anfang durchstarten TempLoop_running = False # Checking for messages to execute code def on_message(client, userdata, msg): print(msg.topic+" "+str(msg.qos)+" "+str(msg.payload)) print("Payload: " + msg.payload.decode()) if msg.payload.decode() == "Temp_Start": start_TempLoop() if msg.payload.decode() == "Temp_Stop": stop_TempLoop() if msg.payload.decode() == "test": print("TESTING...") client.publish("main/messager", "START", qos=0, retain=True) else: pass # Execute things here -> # Getting Temperature address = 0x76 bus = smbus2.SMBus(1) # Load calibration parameters calibration_params = bme280.load_calibration_params(bus, address) def Temperature_loop(): global TempLoop_running while TempLoop_running: data = bme280.sample(bus, address, calibration_params) #Extract temperature, pressure, and humidity temperature_celsius = data.temperature #Print the readings print("Temperature: {:.2f} °C".format(temperature_celsius)) # Nachricht an das entsprechende Topic senden client.publish("Temp/Loop", "Temperature: {:.2f} °C".format(temperature_celsius)) # Wartezeit, um die Ausgabe zu verlangsamen time.sleep(2) # Funktion zum Starten der Temperatur Schleife def start_TempLoop(): global TempLoop_running TempLoop_running = True threading.Thread(target=Temperature_loop).start() # Funktion zum Stoppen der Temperatur Schleife def stop_TempLoop(): global TempLoop_running TempLoop_running = False # Set general data client = mqtt.Client() client.on_message = on_message client.on_connect = on_connect client.connect( "192.xxx", 1883, 60) client.username_pw_set( "xx", "xx" ) client.subscribe( "main/messager", qos=0) # Loop forever client.loop_forever()